Payables and Accrued Liabilities - Schedule of Accounts Payable (Details) - USD ($) $ in Millions	Sep. 30, 2018	Jul. 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Accounts Payable [Line Items]
Payables to servicing and subservicing investors	$ 530
Loans subject to repurchase from Ginnie Mae	231
Accounts payable and other accrued liabilities	165
Payables to GSEs and securitized trusts	95
Accrued bonus and payroll	89
Accrued legal expenses	65
Payable to insurance carriers and insurance cancellation reserves	61
Accrued interest	61
MSR purchases payable including advances	21
Repurchase reserves	9	$ 9
Taxes	8
Lease obligations	5
Derivative financial instruments at fair value	2
Total payables and accrued liabilities	$ 1,342
Predecessor
Accounts Payable [Line Items]
Payables to servicing and subservicing investors				$ 516
Loans subject to repurchase from Ginnie Mae				218
Accounts payable and other accrued liabilities				99
Payables to GSEs and securitized trusts				92
Accrued bonus and payroll				82
Accrued legal expenses				25
Payable to insurance carriers and insurance cancellation reserves				61
Accrued interest				62
MSR purchases payable including advances				10
Repurchase reserves		$ 9	$ 9	9	$ 15	$ 14	$ 18
Taxes				36
Lease obligations				24
Derivative financial instruments at fair value				5
Total payables and accrued liabilities				$ 1,239